Good Artisan = Good Man?

In Chapter 4 of Book II in Nicomachean Ethics, Aristotle says something interesting about the relationship between knowledge and action.

He claims that all that is necessary for the artisan is "the mere knowing." (1105b: 2) But the virtuous man, he must act "knowingly," and have chosen the action "for [its] own sake," and must be "in a stable condition and not able to be moved all the way out of it." (1105a: 32-35)

I am confused about why he thinks there is an actual distinction between what constitutes a good artisan and what constitutes a good man. Does it not make sense to say that an artisan must be just? For he must also be a man, and a businessman at that. Virtue seems requisite for any social behavior to be deemed "good" or "just". Am I missing something crucial about what Aristotle is really saying about this distinction?